HW5.30

 public class Solution
 {
     public static void main(String[] args)
     {
         for(int i = 3; i <= 1000; i++)
             if(isDoublePrime(i))
                 System.out.println("(" + i + ", " + (i + 2) + ")");
     }

     public static boolean isDoublePrime(int n)
     {
         if(isPrime(n) && isPrime(n + 2))
             return true;
         else
             return false;
     }

     public static boolean isPrime(int n)
     {
         if(n == 1)
             return false;
         else if(n == 2)
             return true;
         else
         {
             for(int i = 2; i < n; i++)
             {
                 if(n % i == 0)
                     return false;
             }
             return true;
         }
     }
 }